Elder Audio Beta-3 ED3402 1", 8ohm, bolt on (3-BOLT ONLY) , 1.3" titanium diaphragm compression driver.  

Specifications:
Testing Horn: H4403
Throat diameter	25mm
Rated Impedance	8Ohm
IEC Power	20W
Sensitivity(with horn)	98dB
Frequency response	800-20KHz
Voice coil diameter	34.4mm
Magnet material	Ferrite
Magnetic flux density	1.3t
Voice coil material	Copper
Voice coil formal	Kapton™
Diaphragm material	Titanium
Mounting information
Overall diameter	90mm
Depth	46.2mm
Net weight	0.88Kg

Recommended crossover is 2khz or higher at a minimum of 12dB/octave slope for high power use.  If using with lower power you can cross it much lower

20 watt RMS, same as about any other compression driver with a 1.3" coil.  Don't fall for the supposed high power hype of others, especially in the "car audio" world ;-)  A tweeter will see very little power if crossed over properly and these guys can get extremely loud